Grain Yield, Nitrogen Accumulation, and Its Use Efficiency of Maize ( Zea mays L.) as Influenced by Varying Nitrogen Rates

Nitrogen ( N ) is a key nutrient required for higher yield and better quality of maize that leads to the achievement of food self‐sufficiency in many developing countries. A two‐year field experiment was conducted to evaluate the effect of varying N levels on the performance of hybrid maize, N accumulation, and N use efficiency at Khumaltar, Lalitpur, Nepal, during May to September in 2019 and 2020. The experiment consisted of 7 treatments: 6 levels of N (0, 90, 120, 150, 180, and 210 kg N ha −1 ) with application of P 2 O 5 : K 2 O in 60 : 40 ha −1 and zero plots with no fertilizer application. The experimental was laid out in randomized complete block design with three replications. The results of the experiment revealed that the grain yield, N content, its uptake, efficiency, and economics of hybrid maize production were significantly ( p ≤ 0.001) influenced by difference in N rates. Two years of pooled grain yield produced significantly ( p ≤ 0.001) higher yield of 10.14 Mg ha −1 from application of 210 kg N ha −1 with benefit: cost ratio of 3.22. Likewise, two years of mean N concentrations in grain and stover were 13.13 and 5.32 g kg −1 , respectively, with a total uptake of 117.3 kg ha −1 . The data revealed that partitions of N in maize were 77.5% and 22.5% in grain and stover, respectively. The mean recovery efficiency, agronomic efficiency, and partial factor productivity of N in maize was found to be 48.9%, 20.9 kg kg −1 , and 61.6 kg kg −1 , respectively. Since additional N fertilizer had significant impact on maize productivity, it is advised to apply 210 kg N ha −1 under conditions of similar soil and ecology.